As effects of catechins, there have been reported a suppressing effect on an increase in cholesterol level and an inhibitory effect on α-amylase activity (see, for example, JP-A-60-156614 and JP-A-03-133928). For such physiological effects to manifest, it is necessary for an adult to drink tea as much as 4 to 5 cups in a day. Accordingly, there has been a demand for technology that enables the addition of catechins at high concentration in beverages to facilitate the ingestion of a large amount of catechins. As one of methods for this, catechins are added in a dissolved form to a beverage by using a green tea concentrate (see, for example, JP-A-59-219384, JP-A-4-20589 and JP-A-61-130285) or the like.
In packaged, tea-based beverages, ascorbic acid or the like is also added to stabilize them.
The addition of ascorbic acid or the like in a large proportion however, has a problem that a salty taste stemming from sodium bicarbonate employed upon adjustment of pH is difficult to avoid.